Description:
The overall objective of this presentation is to demonstratea conceptual multiscale, multidomain model of coupling of biogeochemicaland hydrogeological processes during bioremediation of Cr(VI)contaminated groundwater at Hanford 100H site. A slow releasepolylactate, Hydrogen Release Compound (HRCTM), was injected in Hanfordsediments to stimulate immobilization of Cr(VI). The HRC injectioninduced a 2-order-of-magnitude increase in biomass and the onset ofreducing biogeochemical conditions [e.g., redox potential decreased from+240 to -130 mV and dissolved oxygen (DO) was completely removed]. Athree-well system, comprised of an injection well and upgradient anddowngradient monitoring wells, was used for conducting the in situbiostimulation, one regional flow (no-pumping) tracer test, and fivepumping tests along with the Br-tracer injection. Field measurements wereconducted using a Br ion-selective electrode and a multiparameter flowcell to collect hourly data on temperature, pH, redox potential,electrical conductivity, and DO. Groundwater sampling was conducted bypumping through specially designed borehole water samplers.Cross-borehole radar tomography and seismic measurements were carried outto assess the site background lithological heterogeneity and themigration pathways of HRC byproducts through groundwater after the HRCinjection.

Description:
Soluble organics in produced water and refinery effluents represent treatment problems for the petroleum industry. Neither the chemistry involved in the production of soluble organics nor the impact of these chemicals on total effluent toxicity is well understood. The U.S. Department of Energy provides funding for Oak Ridge National Laboratory (ORNL) to support a collaborative project with Shell, Chevron, Phillips, and Statoil entitled ''Petroleum and Environmental Research Forum project (PERF 9844: Manage Water-Soluble Organics in Produced Water''). The goal of this project, which involves characterization and evaluation of these water-soluble compounds, is aimed at reducing the future production of such contaminants. To determine the effect that various drilling conditions might have on water-soluble organics (WSO) content in produced water, a simulated brine water containing the principal inorganic components normally found in Gulf of Mexico (GOM) brine sources was prepared. The GOM simulant was then contacted with as-received crude oil from a deep well site to study the effects of water cut, produced-water pH, salinity, pressure, temperature, and crude oil sources on the type and content of the WSO in produced water. The identities of individual semivolatile organic compounds (SVOCs) were determined in all as-received crude and actual produced water samples using standard USEPA Method (8270C) protocol. These analyses were supplemented with the more general measurements of total petroleum hydrocarbon (TPH) content in the gas (C{sub 6}-C{sub 10}), diesel (C{sub 10}-C{sub 20}), and oil (C{sub 20}-C{sub 28}) carbon ranges as determined by both gas chromatographic (GC) and infrared (IR) analyses. An open liquid chromatographic procedure was also used to differentiate the saturated hydrocarbon, aromatic hydrocarbon, and polar components within the extractable TPH. Inorganic constituents in the produced water were analyzed by ion-selective electrodes and inductively coupled plasma (ICP)-atomic emission spectrometry (AES). The WSO found in produced water samples was primarily polar ...

Description:
This report describes the progress of our research during the first 30 months (10/01/2004 to 03/31/2007) of the original three-year project cycle. The project was terminated early due to DOE budget cuts. This was a joint project between the Tertiary Oil Recovery Project (TORP) at the University of Kansas and the Idaho National Laboratory (INL). The objective was to evaluate the use of low-cost biosurfactants produced from agriculture process waste streams to improve oil recovery in fractured carbonate reservoirs through wettability mediation. Biosurfactant for this project was produced using Bacillus subtilis 21332 and purified potato starch as the growth medium. The INL team produced the biosurfactant and characterized it as surfactin. INL supplied surfactin as required for the tests at KU as well as providing other microbiological services. Interfacial tension (IFT) between Soltrol 130 and both potential benchmark chemical surfactants and crude surfactin was measured over a range of concentrations. The performance of the crude surfactin preparation in reducing IFT was greater than any of the synthetic compounds throughout the concentration range studied but at low concentrations, sodium laureth sulfate (SLS) was closest to the surfactin, and was used as the benchmark in subsequent studies. Core characterization was carried out using both traditional flooding techniques to find porosity and permeability; and NMR/MRI to image cores and identify pore architecture and degree of heterogeneity. A cleaning regime was identified and developed to remove organic materials from cores and crushed carbonate rock. This allowed cores to be fully characterized and returned to a reproducible wettability state when coupled with a crude-oil aging regime. Rapid wettability assessments for crushed matrix material were developed, and used to inform slower Amott wettability tests. Initial static absorption experiments exposed limitations in the use of HPLC and TOC to determine surfactant concentrations. To reliably quantify both benchmark ...

Description:
The Task I pCO/sub 2/ sensor was evaluated in the laboratory and improvements incorporated. Of special note was the redesign of the internal reference electrode which offered greater stability, and improved reliability - a design both smaller and more simple. The ISFET sensor was improved by using a new sensing material which afforded better speed of response. The H/sub 2/S getter was redesigned to overcome seal problems encountered in early Task II tests. The improved probe was thoroughly tested in the laboratory at both moderate and elevated temperatures. This version was also tested at the Magma Electric Company geothermal plant in California. Whereas the laboratory tests were encouraging, the field tests were disappointing, in part due to problems not directly attributable to probe design limitations. In both tests, however, evidence showed that the polymeric seal in the internal ISFET element limited probe life unacceptably in the hot aqueous environment. Electrostatic bonding of silicon to glass for three critical seals is included in the Task II recommended design. All elements of the design were tested successfully in the laboratory.

Description:
This thesis explores feasibility of using coated-wire electrodes to measure chelating agent concentration. Chelating agents are often found in radioactive decontamination solutions because they aid in the removal of radionuclides from contaminated surfaces by increasing their solubility. However, this characteristic will also enhance the mobility of the radionuclide and thus its transport out of a waste disposal site. Coated-wire ion selective electrodes, based on a polyvinylchloride membrane using dioctylphthalate as a plasticizer and dinonylnaphthalenesulfonic acid as a counterion, were constructed for five commonly utilized chelating agents (ethylenediaminetetracetic acid (EDTA), nitrilotriacetic acid (NTA), citric acid, oxalic acid and tartaric add). The EDTA and NTA electrodes` calibration characteristics exhibited acceptable behavior in pure standard solutions. From data obtained while using the EDTA and NTA electrodes in a cement environment, further research needs to be done in the area of ion interference.

Description:
The fabrication of novel multielement microelectrode array sensors is reported. With regard to individual array elements, two main concepts are pursued. One involves the use of relatively non-selective microelectrode elements, coupled with pattern recognition methods, for data analysis. This strategy is most applicable when prior knowledge about the chemical environment is limited, or when mainly qualitative information is sought. The second concept involves the development of arrays containing intrinsically more selective microelectrode elements. Our main concern here is the determination of specific contaminants. Most of our current emphasis is in the selection and development of appropriate elements for microelectrode arrays of this type, with a goal of quantitative analysis for a variety of compounds and elements. Other efforts are concerned with defining the behavior of microelectrodes and devising mass fabrication methods for these sensors. Two designs for the arrays are discussed, one employing photolithographic fabrication methods and another in which individual microelectrodes are encased in glass. Potential applications for these sensors include monitoring for toxic contaminants in natural waters, monitoring waste streams, and process control. 35 refs., 16 figs., 3 tabs.

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